Vent structures are used to provide air passages between the soffit and the attic of a structure to insure the flow of air through the attic to remove hot air and moisture from the attic. When the air passages and soffit of a structure, such as a home, are blocked with insulation or air flow impeding material inadequate attic ventilation results. This causes condensation of moisture in the attic, which accumulates in the attic insulation material. This reduces the insulating effectiveness of the insulating material and may cause damage to the interior of the structure. Inadequate insulation in the attic also results in heat loss in the winter and cool air losses in the summer.
The increased cost of fuel has caused an increased use of insulation materials in the attics of structures. Fiber and foam plastic insulation materials are blown into the crawl or attic space below the roof and between the ceiling joists. Matt-type insulation material is also used. Poor air circulation can result when the spaces between the roof joists and the top wall plate are closed, as these spaces provide the air passages between the soffit and attic.